JP7121242B2 - Vehicle interior material and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vehicle interior material in which an embossed pattern is formed on a laminated sheet material mainly used for seats and doors, and a method for manufacturing the same.

BACKGROUND ART As a vehicle interior material, a fabric having an embossed pattern formed on the surface thereof is widely known. For example, in Patent Document 1, a composite sheet obtained by laminating and integrating a surface material made of a fiber fabric such as a woven fabric, a knitted fabric, or a nonwoven fabric and a cushion layer made of a polyurethane foam material or the like is heated in order to form a deep and clear embossed pattern. A method for producing a vehicle seat upholstery material is described in which embossing is performed between an embossing roll heated to a temperature of 100° C. to 250° C. and a heat roll.

Patent Document 2 proposes to provide a slit and a step in the convex mold portion of the embossing roll to reduce the contact surface with the surface layer fabric and suppress the shine of the fiber fabric, but it has a complicated shape. of embossing rolls are required. In addition, since the projections of the convex mold part of the embossing roll are smooth, it cannot be said that the glossiness of the fiber fabric is sufficiently suppressed when the fiber fabric is heated and pressed.

By the way, a deep and soft embossed pattern is required due to recent design needs. That is, there is an increasing demand for realizing a soft design expression on the surface of the fiber fabric by shaping the cushion layer with an uneven shape. The terms "soft" and "mild" are used in the present application to mean the opposite of "clear embossed pattern" and "sharp embossed pattern".

JP 2007-276285 A Japanese Patent Application Laid-Open No. 2020-142402

However, when embossing is performed between the embossing roll and the heat roll, both of which are heated to the range of 100° C. to 250° C., as in the conventional method, an embossed pattern is formed deeply and clearly on the surface of the fiber fabric. However, a deep and soft embossed pattern could not be formed.

On the other hand, even if the embossing roll and heat roll are set to a lower temperature in order to solve this problem, the embossed pattern becomes halfway weak and a problem arises in that a deep and soft embossed pattern cannot be formed.

The present invention has been made in view of such a technical background, and its object is to provide a vehicle interior material having a soft design representation of an embossed pattern on the surface of a fiber fabric layer, and to provide a cushion layer with an uneven shape. To provide a method for producing an interior material for a vehicle capable of reducing damage (crushing) of a fiber fabric layer by shaping and imparting a soft design expression to the surface of the fiber fabric layer.

In order to achieve the above object, the present invention provides the following means.

[1] A vehicle interior material in which an embossed pattern is formed on a composite sheet in which a fiber fabric layer and a cushion layer are laminated and integrated,
An interior material for a vehicle, wherein the thickness change rate of the fiber fabric layer of the embossed recesses is 20% or more and 50% or less, and the thickness change rate of the composite sheet is 30% or more.

[2] A method for manufacturing an interior material for a vehicle, in which an embossed pattern is formed on a composite sheet in which a fiber fabric layer and a cushion layer are laminated and integrated,
The fiber fabric layer side of the composite sheet is supplied between an embossing roll having embossed protrusions protruding on the surface and a backup roll having a metal surface, and the embossing roll and the backup roll are supplied. A heating pressing step of heating and pressing the composite sheet between
In the heat pressing step, the embossing roll has a temperature range of 40°C to 105°C, the backup roll has a temperature range of 200°C to 235°C, and
A method for manufacturing an interior material for a vehicle, wherein the temperature of the embossing roll is lower than the temperature of the backup roll by 100°C or more.

[3] The method for producing a vehicle interior material according to the above item 2, wherein in the hot pressing step, the surface speed ratio of the backup roll to the embossing roll is 1.0 to 1.05 .

[4] In the heat-pressing step, the thickness change rate of the fiber fabric layer of the embossed recesses of the composite sheet is 20% or more and 50% or less, and
4. The method for producing a vehicle interior material according to claim 2 or 3, wherein the thickness change rate of the composite sheet is 30% or more .

In the invention [1], in a vehicle interior material in which an embossed pattern is formed on a composite sheet in which a fiber fabric layer and a cushion layer are laminated and integrated, the thickness change rate of the fiber fabric layer in the recesses of the embossed pattern is 20%. or more and 50% or less, and the thickness change rate of the composite sheet is 30% or more. The fiber fabric stretched in the uneven shape of the cushion layer can be used as a vehicle interior material having a soft design expression on the surface.

In the invention [2], rather than transferring the convex shape of the embossing roll to the surface of the fiber fabric, the fiber fabric is pulled by the uneven shape of the cushion layer by forming the uneven shape on the cushion layer. It is possible to make a soft design expression appear on the surface.

In the invention [3], by setting the surface speed ratio of the backup roll to the embossing roll in the range of 1.0 to 1.05 , the cushion layer is synchronized or pushed in by the rotation of the backup roll, so that the cushion layer is smooth. Concavo-convex shape can be formed.

In the invention [4], the thickness change rate of the fiber fabric layer of the embossed recesses of the composite sheet is 20% or more and 50% or less, and the thickness change rate of the composite sheet is 30% or more , Rather than transferring the convex shape of the embossing roll to the surface of the fiber fabric layer, the uneven shape is formed on the cushion layer and the fiber fabric pulled to the uneven shape of the cushion layer is formed with a soft design expression on the surface. can be done.

1 is a schematic plan view showing an embodiment of a vehicle interior material according to the present invention; FIG. FIG. 2 is a schematic AA cross-sectional view of the vehicle interior material shown in FIG. 1; FIG. 4 is an explanatory diagram of a thickness change rate in the vehicle interior material according to the present invention; It is a schematic diagram which shows an example of the conventional interior material for vehicles. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows an example of the roll embossing apparatus used with the manufacturing method of the vehicle interior material of this invention. 1 is a cross-sectional photograph of a vehicle interior material of Example 1. FIG. 4 is a cross-sectional photograph of a vehicle interior material of Comparative Example 4. FIG.

Next, an embodiment of a vehicle interior material according to the present invention will be described with reference to FIGS. 1 to 3. FIG.

A vehicle interior material 1 according to the present invention is a vehicle interior material in which an embossed pattern is formed on a composite sheet 4 in which a fiber fabric layer 2 and a cushion layer 3 are laminated and integrated. The thickness change rate of the fiber fabric layer 2 is 20% or more and 50% or less, and the thickness change rate of the composite sheet 4 is 30% or more.

The fiber fabric layer 2 of the present invention is not particularly limited, and examples thereof include woven fabrics, knitted fabrics, and non-woven fabrics. Examples of the fibers that constitute the fiber fabric layer 2 include synthetic fibers such as polyester fibers, polyamide fibers, and polyacrylonitrile fibers, cotton fibers, and rayon fibers. You may combine these suitably.

Soft urethane foam is preferable for the cushion layer 3 of the present invention, and the density, hardness, and thickness of the soft urethane foam can be selected within a range in which the cushioning property is good. Preferably, the density is in the range of 15 Kg/m ³ to 45 Kg/m ³ , the hardness is in the range of 60N to 180N, and the thickness is in the range of 1 mm to 10 mm. It is preferable that the soft urethane foam has circular knitted fabric laminated on the back side as the back base fabric because it improves the workability of cutting and sewing, etc., as well as good process passability.

In the present invention, the composite sheet 4 is obtained by laminating and integrating the fiber fabric layer 2 and the cushion layer 3 . Although the method of lamination and integration is not particularly limited, it may be carried out by using an adhesive or by a frame lamination method. Among them, the frame lamination method is preferable from the viewpoint of adhesive strength, and the strength of integration of the fiber fabric layer 2 and the cushion layer 3 in the state where the embossed pattern is formed can be further improved.

In the present invention, the thickness change rate of the fiber fabric layer 2 in the embossed recesses 5 is 20% or more and 50% or less, and the thickness change rate of the composite sheet 4 is 30% or more. Here, as shown in FIG. 3, the thickness change rate of the fiber fabric layer 2 of the embossed recesses 5 and the thickness change rate of the composite sheet 4 are obtained by taking the thickness of the fiber fabric layer 2 of the embossed protrusions 6 as T ₀ , the thickness of the fiber fabric layer 2 of the embossed recesses 5 is T ₁ , the thickness of the composite sheet 4 of the embossed recesses 6 is H ₀ , the thickness of the composite sheet 4 of the embossed recesses 5 is H ₁ . Then, they are calculated by the following formulas. The thickness was measured using a microscope (HOZAN L-KIT581) for each section.
Thickness change rate (%) of the fiber fabric layer 2 in the recesses 5 of the embossed pattern = 100 × (T ₀ - T ₁ )/T ₀
Thickness change rate (%) of composite sheet 4 in embossed recesses 5 = 100 x (H ₀ - H ₁ )/H ₀

By adopting such a configuration, the vehicle interior material 1 of the present invention is a cushion layer in which the uneven shape is formed rather than the uneven shape is transferred to the surface of the fiber fabric layer 2 by the embossing roll. A vehicle interior material having a soft design expression on the surface of the fiber fabric layer 2 pulled into the uneven shape of 3 can be obtained. That is, the embossed pattern of the vehicle interior material 1 of the present invention is expressed as an embossed pattern on the fiber fabric layer 2 following the uneven shape formed on the cushion layer 3, and the unevenness of the mold is directly transferred. Unlike conventional embossed patterns that are deeply and clearly formed like this, the design is fluffy and soft.

By setting the thickness change rate of the fiber fabric layer 2 in the embossed recesses 5 to 20% or more and 50% or less and the thickness change rate of the composite sheet 4 to be 30% or more, the composite sheet is more complex than the thickness change rate of the fiber fabric layer 2. The thickness change rate of the seat 4 is much larger, and the vehicular interior material 1 having a soft design expression in which the fiber fabric layer 2 is reliably pulled by the uneven shape of the cushion layer 3 can be obtained. More preferably, the thickness change rate of the fiber fabric layer 2 in the embossed recesses 5 is in the range of 20% to 50%, and the thickness change rate of the composite sheet 4 is in the range of 30% to 70%.

On the other hand, as shown in FIG. 4, the conventional vehicle interior material has a sharper embossed pattern, which is clearly different from the present invention and cannot be said to have the design expression of the present invention.

Next, an example of a method for manufacturing the vehicle interior material 1 of the present invention will be described with reference to FIGS.

A method for manufacturing a vehicle interior material 1 according to the present invention is a method for manufacturing a vehicle interior material 1 in which an embossed pattern is formed on a composite sheet 4 in which a fiber fabric layer 2 and a cushion layer 3 are laminated and integrated, The fiber fabric layer 2 side of the composite sheet 4 is supplied between an embossing roll 8 having a projected embossing protrusion on the surface and a backup roll 9 having a metal surface, and the embossing roll 8 is supplied with the fiber fabric layer 2 side of the composite sheet 4 on the embossing roll 8 side. and a backup roll 9, in which the temperature of the embossing roll 8 is in the range of 40°C to 105°C, and the temperature of the backup roll 9 is in the range of 200°C to 235°C. °C, and the temperature of the embossing roll 8 is lower than the temperature of the backup roll 9 by 100°C or more.

An example of a roll embossing device is shown in FIG. In order to form an embossed pattern on the composite sheet 4 using the roll embossing device 7, a rotatably provided embossing roll 8 and an embossing roll 8 (embossing protrusions protruding from the surface are not shown) are used. ), the composite sheet 4 is supplied between the embossing roll 8 and the back-up roll 9 rotatably provided facing the embossing roll 8 . The composite sheet 4 may be supplied between the embossing roll 8 and the backup roll 9 while winding around the backup roll 9 as shown in FIG. This is preferable because feeding of the composite sheet 4 is stabilized.

Although not shown in FIG. 5, the embossing roll 8 and the backup roll 9 are each equipped with a heating means. The embossing roll 8 has embossed projections on its surface, and the backup roll 9 has a metal surface. The material of the embossing roll 8 and the backup roll 9 is preferably carbon steel S25C or S45C because of its good thermal conductivity. The temperature of the embossing roll 8 is set lower than the temperature of the backup roll 9 by 100° C. or more, and the supplied composite sheet 4 is heated and pressed between the embossing roll 8 and the backup roll 9 .

In the heat-pressing step, the temperature of the embossing roll 8 is set lower than the temperature of the backup roll 9 by 100° C. or more. By setting the temperature lower than 100° C., the cushion layer 3 on the back side of the fiber fabric layer 2 of the composite sheet 4 has an uneven shape. A soft design expression can be made to appear on the surface of the fiber fabric layer 2 stretched to the outside. In addition, since the thickness change rate of the fiber fabric layer 2 in the embossed recesses 5 of the composite sheet 4 is 20% or more and 50% or less, and the thickness change rate of the composite sheet 4 is 30% or more, the fiber fabric layer Rather than transferring the convex shape of the embossing roll 8 to the surface of the embossing roll 8, a soft design expression is formed on the surface of the fiber fabric 2 that has been formed into the uneven shape on the cushion layer 3 and pulled into the uneven shape of the cushion layer 3. can do.

Although the number of embossing protrusions protruding from the embossing roll 8 is not particularly limited, a plurality of protrusions is preferable. Moreover, the height of the embossed protrusions, the interval between the embossed protrusions, and the size of the embossed protrusions are not particularly limited. Of course, the projected embossed convex portion may be in the shape of a continuous line. In addition, although it depends on the embossed pattern to be formed, the height of the embossed protrusions is preferably in the range of +1.0 mm to +5.0 mm more than the total thickness of the composite sheet 4, and the distance between the embossed protrusions is The range of +1.0 mm to +50.0 mm is preferable from the total thickness of the This range is preferable because the embossed pattern can be made more distinct and plump.

According to this manufacturing method, rather than transferring the convex shape to the surface of the fiber fabric 2 by the embossing roll 8, the uneven shape of the cushion layer 3 is formed by forming the uneven shape. A soft design expression can appear on the surface of the fiber fabric 2 thus formed. That is, the embossed pattern of the vehicle interior material 1 of the present invention is expressed as an embossed pattern on the fiber fabric layer 2 following the uneven shape formed on the cushion layer 3, and the unevenness of the mold is attached as it is. Unlike conventional embossed patterns that are deeply and clearly formed like this, the design is fluffy and soft.

In the heat-pressing step, since the cushion layer 3 is synchronized or pressed by the rotation of the backup roll 9, the uneven shape can be formed on the cushion layer 3. Therefore, the surface speed ratio of the backup roll 9 to the embossing roll 8 is is preferably in the range of 1.0 to 1.25. If the surface speed ratio is less than 1.0, the soft uneven shape may be weakened and flattened. This is not preferable as it may occur. More preferably, the surface velocity ratio is in the range of 1.0 to 1.05.

In the heat-pressing step, the uneven shape can be reliably formed by the cushion layer 3. Therefore, the embossing roll 8 has a temperature range of 40°C to 105°C, and the backup roll 9 has a temperature range of 200°C to 235°C. preferable. If the temperature of the embossing roll 8 is lower than 40°C, the embossed pattern may not become clear, and if the temperature of the embossing roll 8 is higher than 105°C, sharp recesses may be formed in the fiber fabric layer 2, which is not preferable. . If the temperature of the backup roll 9 is lower than 200°C, it may become difficult to shape the cushion layer 3 sufficiently. , there is a risk of fusion bonding to the backup roll 9, which is not preferable.

Moreover, it is preferable that the pressure between the embossing roll 8 and the backup roll 9 is in the range of 2 to 60 kg/cm ² and the passing speed of the composite sheet 4 is in the range of 0.1 to 5 m/min. By setting the pressure and passing speed within this range, the formation of a soft and clear embossed pattern is more stable, which is preferable.

Next, specific examples of the present invention will be described, but the present invention is not particularly limited to these examples.

<Materials used, etc.>
Fiber fabric layer: fabric (thickness 1.0 mm)
Cushion layer: soft urethane foam (density 20 kg/m ³ , thickness 5 mm, product name EL67 manufactured by INOAC Corporation)
Back base fabric of cushion layer: Circular knitted fabric (basis weight 40 g/m ² )
Composite sheet: A cushion layer is integrated with the fiber fabric layer by frame lamination (total thickness: 6.0 mm).

Using a roll embossing device 7 as shown in FIG. 5, an embossed pattern was formed on the composite sheet prepared in advance. That is, the surface speed ratio of the backup roll 9 to the embossing roll 8 was set to 1.0, the passing speed of the composite sheet was set to 2 m / min, and the embossing roll 8 having a surface temperature of 100 ° C. and the backup roll having a surface temperature of 230 ° C. The composite sheet was hot-pressed with a roll 9 at a pressure of 50 kg/cm ² to form an embossed pattern on the composite sheet to obtain an interior material for a vehicle. The thickness change rate of the fiber fabric layer in the embossed recesses of the obtained vehicle interior material was 25%, and the thickness change rate of the composite sheet in the embossed recesses was 38%. In addition, FIG. 6 is a cross-sectional photograph of the obtained vehicle interior material. The embossed pattern of the vehicle interior material was evaluated as "◯", and the concave portion was evaluated as "⊚".

A vehicle interior material was obtained in the same manner as in Example 1, except that the surface speed ratio of the backup roll 9 to the embossing roll 8 was 1.05. The thickness change rate of the fiber fabric layer in the embossed recesses of the vehicle interior material was 30%, and the thickness change rate of the composite sheet in the embossed recesses was 45%. By feeding the back up roll 9, the feeling of soft unevenness was improved, and the evaluation of the embossed pattern of the obtained vehicle interior material was "⊚" and the evaluation of the concave portion was "⊚".

A vehicle interior material was obtained in the same manner as in Example 1, except that the surface speed ratio of the backup roll 9 to the embossing roll 8 was set to 1.10. The thickness change rate of the fiber fabric layer in the embossed recesses of the vehicle interior material was 30%, and the thickness change rate of the composite sheet in the embossed recesses was 52%. By feeding the back up roll 9, the feeling of soft unevenness was improved, and the evaluation of the embossed pattern of the obtained vehicle interior material was "⊚" and the evaluation of the concave portion was "⊚".

A vehicle interior material was obtained in the same manner as in Example 1, except that the surface speed ratio of the backup roll 9 to the embossing roll 8 was 1.20. The thickness change rate of the fiber fabric layer in the embossed recesses of the vehicle interior material was 34%, and the thickness change rate of the composite sheet in the embossed recesses was 65%. By feeding the back up roll 9, the feeling of soft unevenness was improved, and the evaluation of the embossed pattern of the obtained vehicle interior material was "⊚" and the evaluation of the concave portion was "⊚".

A vehicle interior material was obtained in the same manner as in Example 1 except that the surface temperature of the embossing roll 8 was changed to 60°C. The thickness change rate of the fiber fabric layer in the embossed recesses of the vehicle interior material was 22%, and the thickness change rate of the composite sheet in the embossed recesses was 32%. The thickness change rate of the fiber fabric layer was smaller than that of Example 1. That is, although the feeling of soft unevenness was reduced, the evaluation of the obtained embossed pattern was "Good" and the evaluation of the depressions was "A".

<Comparative Example 1>
In Example 1, the procedure was the same as in Example 1 except that the surface temperature of the embossing roll 8 was 190°C and the surface temperature of the backup roll 9 was 100°C. The thickness change rate of the fiber fabric layer in the embossed recesses was 82%, and the thickness change rate of the composite sheet material in the embossed recesses was 15%. The evaluation of the embossed pattern was "xx", and the evaluation of the depressions was "x".

<Comparative Example 2>
In Example 1, the procedure was the same as in Example 1 except that the surface temperature of the embossing roll 8 was 120°C. The thickness change rate of the fiber fabric layer in the embossed recesses was 56%, and the thickness change rate of the composite sheet in the embossed recesses was 38%. The evaluation of the embossed pattern was "x", and the evaluation of the depressions was "Δ".

<Comparative Example 3>
Example 1 was the same as Example 1, except that the surface temperature of the embossing roll 8 was set to 120° C. and the surface speed ratio of the backup roll 9 to the embossing roll 8 was set to 1.10. The thickness change rate of the fiber fabric layer in the embossed recesses was 63%, and the thickness change rate of the composite sheet in the embossed recesses was 54%. The evaluation of the embossed pattern was "x", and the evaluation of the depressions was "Δ".

<Comparative Example 4>
The procedure of Example 1 was repeated except that the surface temperature of the embossing roll 8 was set to 150° C. and the surface speed ratio of the backup roll 9 to the embossing roll 8 was set to 1.10. The thickness change rate of the fiber fabric layer in the embossed recesses was 70%, and the thickness change rate of the composite sheet in the embossed recesses was 56%. 7 is a cross-sectional photograph of Comparative Example 4. FIG. The evaluation of the embossed pattern was "x", and the evaluation of the concave portion was "x".

<Comparative Example 5>
Example 1 was the same as Example 1 except that the surface temperature of the embossing roll 8 was 180° C. and the surface speed ratio of the backup roll 9 to the embossing roll 8 was 1.10. The thickness change rate of the fiber fabric layer in the embossed recesses was 75%, and the thickness change rate of the composite sheet in the embossed recesses was 68%. The evaluation of the embossed pattern was "x", and the evaluation of the concave portion was "x".

As is clear from Table 1, in the vehicle interior materials of Examples 1 to 5, the surface of the fiber fabric layer was not excessively compressed, and the cushion layer was formed with uneven shapes, resulting in a soft embossed pattern. had a design expression of Moreover, since the vehicle interior materials of Examples 2 to 4 were fed with the backup roll 9 to form uneven shapes, they had larger, clearer and softer embossed patterns.

On the other hand, in Comparative Examples 1 to 4, the fiber fabric layer was also heat-compressed and the uneven shape was formed in the fiber fabric layer. It didn't look like it.

<Appearance evaluation method (embossed pattern)>
After arranging them on a desk with the embossed pattern facing up, the uneven shape was visually observed from directly above the embossed pattern and from a direction at an angle of 45 degrees, compared with Comparative Example 1, and evaluated according to the following criteria. A judgment of “○” or higher was regarded as a pass.
(criterion)
"A": The unevenness is mild, and the overall composite sheet has large and clear unevenness.
"Good": The unevenness is mild, and the composite sheet as a whole also has unevenness.
"Δ": The uneven shape is mild, and the uneven shape of the entire composite sheet is small.
"X": The uneven shape is sharp, and the entire composite sheet also has an uneven shape.
"XX": The uneven shape is sharp, and the overall composite sheet has a small uneven shape.

<Appearance evaluation method (recess)>
The presence or absence of damage (collapse) of the fibers of the fiber fabric layer in the concave portions of the embossed pattern was visually observed in comparison with Comparative Example 1, and evaluated according to the following criteria. A judgment of “○” or higher was regarded as a pass.
(criterion)
"A": No crushing is observed in the fibers.
"◯": Almost no crushing is observed in the fibers.
"△": Collapse is recognized in the fiber.
"X": Collapse is clearly observed in the fibers.

The vehicle interior material according to the present invention can be suitably used mainly for seats and doors. Moreover, it is suitable as a manufacturing method for forming an embossed pattern on a composite sheet material.

Reference Signs List 1 Vehicle interior material 2 Fiber fabric layer 3 Cushion layer 4 Composite sheet 5 Embossed concave portion 6 Embossed convex portion 7 Roll embossing Apparatus 8...Embossing roll 9...Backup roll _T0 ...Thickness T1 of the fiber fabric layer 2 in the convex portions of the embossed pattern ₁ ...Thickness _H0 of the fiber fabric layer 2 in the concave portions of the embossed pattern . . . Thickness H of composite sheet 4 having embossed convex portions ₁ . . . Thickness of composite sheet 4 having embossed concave portions

Claims (4)

An interior material for a vehicle in which an embossed pattern is formed on a composite sheet in which a fiber fabric layer and a cushion layer are laminated and integrated,
An interior material for a vehicle, wherein the thickness change rate of the fiber fabric layer of the embossed recesses is 20% or more and 50% or less, and the thickness change rate of the composite sheet is 30% or more. A method for producing a vehicle interior material for forming an embossed pattern on a composite sheet in which a fiber fabric layer and a cushion layer are laminated and integrated,
The fiber fabric layer side of the composite sheet is supplied between an embossing roll having embossed protrusions protruding on the surface and a backup roll having a metal surface, and the embossing roll and the backup roll are supplied. A heating pressing step of heating and pressing the composite sheet between
In the heat pressing step, the embossing roll has a temperature range of 40°C to 105°C, the backup roll has a temperature range of 200°C to 235°C, and
A method for manufacturing an interior material for a vehicle, wherein the temperature of the embossing roll is lower than the temperature of the backup roll by 100°C or more. 3. The method for producing an interior material for a vehicle according to claim 2, wherein in the hot pressing step, the surface speed ratio of the backup roll to the embossing roll is 1.0 to 1.05 . In the heat pressing step, the thickness change rate of the fiber fabric layer of the embossed recesses of the composite sheet is 20% or more and 50% or less, and
4. The method for producing a vehicle interior material according to claim 2 or 3, wherein the thickness change rate of the composite sheet is 30% or more .

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